Extreme rainfall on the eastern seaboard of Australia

The eastern seaboard of Australia is a different climatological entity to the rest of eastern Australia. Major climate drivers such as the El Niño – Southern Oscillation (ENSO) are not dominant in driving climate variability in this region (Timbal, 2010). Recent research has suggested that extreme rainfall along the eastern seaboard may be strongly influenced by east coast lows which in turn do not appear to respond strongly to these modes of variability (Dowdy et al., 2011). The aim of this research was to investigate extreme rainfall along the eastern seaboard and its relationship with east coast lows.

Extreme rainfall was defined as the daily rainfall total of 1% Probability of exceedance (Pe) – equivalent to 1 in 100 year average recurrence interval. This was calculated using the Generalised Extreme Value (GEV) theory using the Bureau of Meteorology operational gridded rainfall data originally developed as part of the Australian Water Availability Project (AWAP). Station data from the Australian Bureau of Meteorology's observation network were also used to calculate 1% Pe and for intercomparison between gridded and observed values. Work is currently underway on trend analysis using Extreme Value Analysis (EVA). This presentation will focus on the results from the GEV and EVA trend analysis of extreme rainfall on the eastern seaboard of Australia and its relationship with east coast lows.

References

Timbal, B. 2010. "The Climate of the Eastern Seaboard of Australia: A challenging entity now and for future projections.", IOP Conf. Seried: Earth and Environmental Science, 11 (012013).

Dowdy, A., Mills, G., and Timbal, B., 2011. "Large-scale indicators of Australian East Coast Lows and associated impacts.", CAWCR Technical report, 37, pp104.